Consolidated microcapsules with double alginate shell containing paraffin for latent heat storage

Abstract

Double-shell alginate microcapsules containing paraffin phase change material (PCM) were prepared for latent heat storage by a method of repeated interfacial coacervation/crosslinking.The proposed process consisted of three main steps: (1) preparation of paraffin containing core particles by dripping an O/W emulsion of melted paraffin and aqueous sodium alginate into a calcium chloride ionic cross-linking solution, (2) encapsulation of the core particles into double alginate shell by ionic gelation/crosslinking by repeated interactions between the sodium alginate and calcium chloride solutions, and (3) consolidation of the capsule shells by contact heat treatment. The effects of process parameters such as the sodium alginate concentration, the calcium chloride concentration in certain stages of the process, and the contact time between the formed core particles and the surrounding alginate solution on the paraffin content and the mean diameter of capsules were studied by experimental design and statistical evaluations. The prepared PCM capsules had uniform sizes, core/shell structure, double-walled non-porous alginate coating, tunable void space inside the core, and suitably high paraffin content at properly selected process conditions, corresponding to 95.0 J/g melting and 91.7 J/g freezing latent heat capacity. Thermogravimetric analysis and repeated thermal cycling evidenced good thermal stability, and proper mechanical strength for leakage free microcapsules.

Antimicrobial functionalization of Ca alginate‐coconut oil latent heat storing microcapsules by Ag nanoparticles

“…In our group a novel method was developed to use Ca alginate to entrap paraffin PCM in order to obtain coreshell microcapsules with high heat storing capacity. 18 Recently, entirely eco-friendly microparticles were prepared by a scaled-up procedure using the same shell material, however, encapsulating coconut oil. 19 These fully bio-originated microcapsules possessed high PCM content (81.1% m/m) together with compact shell.…”

Thermal buffering effect of a packaging design with microencapsulated phase change material

“…PCMs are used for latent heat storage to increase thermal energy capacity in different systems . Microencapsulation technology is very important for producing more useful PCMs and has been extensively used in the areas of pharmaceutical, food, catalyst, applications to textile fabrics, concrete mixes for sustainable buildings, energy storage, and thermal release performances . The microencapsulation techniques provide stability to PCMs (core materials).…”

“…17 PCMs are used Abbreviations: DSC, differential scanning calorimeter; FTIR, Fourier transform infrared; mPCM, Microencapsulated phase change material; P1, Packaging design with mPCM; P2, Packaging design with PCM; P3, Reference packing; PCM, Phase change material; SEM, Scanning electron microscopy; TGA, Thermo gravimetric analysis List of Nomenclature: T p , Temperature of package with PCM; T r , Temperature of reference without PCM; ΔT, Temperature different; ΔH, Enthalpy (J/g); ΔH m , Melting enthalpy (J/g); ΔH mPCM , Latent heat of MPCM (J/g); ΔH PCM , Latent heat of PCM (core material) (J/g for latent heat storage 18 to increase thermal energy capacity in different systems. 16,19 Microencapsulation technology is very important for producing more useful PCMs [20][21][22] and has been extensively used in the areas of pharmaceutical, 23,24 food, 25 catalyst, 26,27 applications to textile fabrics, 28 concrete mixes for sustainable buildings, 29 energy storage, [30][31][32][33] and thermal release performances. 34 The microencapsulation techniques provide stability to PCMs (core materials).…”

A novel method for producing bi-component thermo-regulating alginate fiber from phase change material microemulsion

“…[13][14][15] With regards to the application of alginate in thermo-regulation/heat storage products, there does not have a better method than encapsulation of PCM by alginate yet, even though the encapsulation is not easy owing to the physical form of alginate of a hydrogel with small or large pores. 16 Nemeth 16 prepared and investigated double-shell alginate microcapsules containing paraffin PCM for latent heat storage. Wang et al 17 fabricated alginate macro-capsules containing n-octadecane PCM shapestabilized with high-density polyethylene.…”